Perfect for extending headphone cables that do not have builts-in mute and volumes controls. The mute switching on the front slides up and down to mute or turn on the headsets microphone. The wheel on the side scrolls up and down to adjust the volumes. metal casing and gold-plate connectors, Active Noise Cancellation technology ensures signals transmission, seamlessly transmits stereo sound for sound . The cable is soft and durability and can be flexed more than 10,000times; double shielding ensures that signals loss is minimized.